The Hydrogen Economy, Hydrogen Sources, and the Science Behind These

The hydrogen-filled Hindenburg in 1936 or 1937. Photo from DeGolyer Library at Southern Methodist University.

THE HYDROGEN ECONOMY

The hydrogen economy is a hypothetical future in which energy can be bought, sold, stored, and transported in a currency of hydrogen, much like today’s energy is often exchanged in electricity. Because hydrogen doesn’t need to be attached to the electricity grid, it can be used in forms of transportation like buses and cars.

The end-user of the hydrogen, for example an automobile driver, doesn’t experience significant pollution beyond the formation of water from burning the hydrogen.

Hydrogen, a gas, isn’t a fuel like gasoline or coal; hydrogen is a way to store and transport energy made from other fuels, like a battery or electricity. Unlike fossil fuels, pure hydrogen isn’t stable, so forming hydrogen in the first place requires energy and produces carbon dioxide, and storing hydrogen involves special considerations because this light gas is very flammable and also quickens rust and oxidation in pipelines and storage containers.

HOW HYDROGEN IS DIFFERENT FROM FOSSIL FUELS

Allowing hydrogen (a gas) to burn in the presence of oxygen releases that stored energy in the form of heat. Hydrogen can also be reacted in a fuel cell to produce electricity. In either case, electricity or heat can then be used to power cars or any number of other devices. Gasoline, biofuels, wood, and other carbon-based fuels all produce carbon dioxide when they are burned, and rising carbon dioxide levels are widely implicated in climate change. Burning hydrogen produces energy, water and a few trace compounds, but it doesn’t produce carbon dioxide.

2 H2 (hydrogen gas) + O2 (oxygen gas) = 2 H2O (water vapor) + energy

It’s unclear what widespread emission of water vapor could do. According to recent published estimates, atmospheric water vapor is responsible for 75 percent of the greenhouse effect. However, water vapor can condense, and it’s naturally-occurring in the atmosphere. It is much easier to trap and transform to liquid than the carbon dioxide normally emitted by burning gasoline. Carbon dioxide won’t form a liquid at atmospheric temperatures and will solidify into dry ice only below -108.4 Fahrenheit, so proponents say it can be easier to trap the vapor in hydrogen-powered machines.

If the energy used to generate and purify and store and ship hydrogen doesn’t require emitting greenhouse gases or toxics, proponents argue that hydrogen is a clean alternative.

SOURCES OF HYDROGEN: THE UNFORTUNATE REALITY TODAY

Hydrogen, not carbon, is the most prevalent atom in the human body. There are two hydrogen atoms in every water molecule, and as many as hundreds of hydrogen atoms on the basic building blocks of life, from DNA to plant fibers. Nonetheless, harvesting the hydrogen atoms out of any of these structures to make hydrogen fuel isn’t easy because hydrogen likes to be bonded to carbon or oxygen; it doesn’t like to be elemental gas.

To produce pure hydrogen today, industries use primary fuel source like petroleum, natural gas, coal, or biomass. Through chemical processing, the hydrogen atoms are stripped from the fuel by way of an input of energy from electricity (more than 80 percent of which comes from fossil fuels in the United States). Furthermore, the leftover material from the stripping is carbon dioxide, the same carbon dioxide that would have been produced if the fuel was burned in an engine.

The reactions for various fuel to hydrogen conversions can be found on the U.S. Department of Energy website here.

Hydrogen can also be produced, at great energy loss, through the electrolysis of water: using electricity, water is divided into its constituents, hydrogen and oxygen. However, water electrolysis is the least carbon-neutral hydrogen production method, and it is very expensive ($3 to $6 per kilogram instead of a little more than $1 in the case of using coal for hydrogen), according to the U.S. Energy Information Administration. All hydrogen production methods result in a net energy loss.

Climate change is the shift in long-term, global weather patterns due to human action; it’s not exclusive to warming or cooling.

Climate change includes any change resulting from different factors, like deforestation or an increase in greenhouse gases. Global warming is one type of climate change, and it refers to the increasing temperature of the surface of Earth. According to NASA, the term global warming gained popular use after geochemist Wallace Broecker published a 1975 paper titled Climatic Change: Are We on the Brink of a Pronounced Global Warming?

Since 1880, the average surface temperature of the Earth has increased by roughly 0.9 degrees Fahrenheit, but the rate it’s increasing is faster than that, depending on which region you live in. If you’re closer to the equator, temperatures are increasing more slowly. The fastest increase in temperatures in the United States is in Alaska, where average temperatures have been increases by more than 3 degrees Fahrenheit per century. For a graph of average global temperatures by year, see the NASA website here.

HOW GREENHOUSE GASES RELATE TO CLIMATE CHANGE

Greenhouse gases are those thought to contribute to the greenhouse effect, an overall warming of the Earth as atmospheric gases trap electromagnetic radiation from the sun that would otherwise have been reflected back out into space.

Noteworthy greenhouse gases are methane, nitrous oxide, carbon dioxide, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). These gases are thought to affect the climate directly and indirectly, even though they constitute only a small fraction of the blanket of gases that make up the atmosphere.

Currently, the composition of the atmosphere is mostly nitrogen and oxygen, with just 0.033 percent carbon dioxide and all other gases accounting for even less.

WHICH GASES CONTRIBUTE THE MOST?

According to 2010 models cited by NASA, 20 percent of the greenhouse effect is attributed directly to carbon dioxide and 5 percent to all other greenhouse gases. The remaining 75 percent of the greenhouse effect is thought to be due to water vapor and clouds, which are naturally-occurring. However, even though carbon dioxide and the other greenhouse gases are such a small percentage of the total gas in the atmosphere, they affect when, where and how clouds form, so greenhouse gases have some relevance when it comes to 100 percent of the greenhouse effect. Carbon dioxide is thought to modulate the overall climate, like a atmospheric thermostat.

Some greenhouse gases are produced in natural processes, like forest fires, animal manure and respiration, or volcanic eruptions. However, the majority of new greenhouse gases are produced from industrial processes and energy production.

The four largest human sources of U.S. greenhouse gases in 2009 were energy, non-fuel use of fossil fuels, natural gas production, and cement manufacture, in descending order. Non-fuel, greenhouse gas-producing applications of fuels include industrial production like asphalt, lubricants, waxes and other . Emissions related to cement manufacture happen when limestone (calcium carbonate) is reacted with silica to make clinker, the lumps ground to make cement. ( Emissions of Greenhouse Gases in the United States 2009: Independent Statistics & Analysis.)

“Cap-and-Trade” and Carbon Tax Proposals

The idea of “cap-and-trade” first emerged in the United States in the 1960s as a device to get the free economy to control pollution, folding in the cost of pollution instead of telling industry how to stop polluting. Often called emission trading, in a working cap-and-trade system, industries that release undesirable compounds into the air, water, or soil have limits of how much they can emit based upon pollution permits. Depending on the system, polluters either are given or have to buy their permits. The government establishes how much total pollution that the permits will grant, an umbrella cap on the economy. If an industry participant wants to release more than the permit allows, they buy the right from another industry player, if available, or perhaps face penalties, depending on the details.

Cap-and-trade can be used to regulate any pollutant, not only carbon dioxide or other greenhouse gases. The U.S. Environmental Protection Agency has three cap-and-trade programs, none of which apply to greenhouse gases. They aim to combat acid rain by reducing sulfur dioxide and nitrous oxide compounds, mostly an issue with coal power.

There is no U.S. cap-and-trade for carbon dioxide, though proposals have been raised regularly, and the U.S. House of Representatives passed an emissions trading program in an energy bill in 2009, but the bill hasn’t been approved by the U.S. Senate, as of June 2011.

Australia has been considering a cap-and-trade program for carbon dioxide, but that too hasn’t been implemented as of June 2011. The European Union has had a carbon emissions trading program since 2005.

CAP-AND-TRADE IN THE UNITED STATES

In the United States, the Acid Rain Program‘s cap-and-trade system has successfully reduced pollution and cost industry far less than expected, at $3 billion per year instead of the feared $25 billion per year, according to a study [that I haven’t found yet] in the Journal of Environmental Management. Savings from cleaner air and water and avoided death and illness are estimated in the range of $100 billion per year, according to the EPA.

However, acid rain chemicals are easier to tame than carbon dioxide. The goal for the subjects of U.S. regulations today – nitrous oxide and sulfur dioxide – is as little as possible. Everyone agrees that these pollutants are bad for the environment and people, and there was a commercially-available solution for nitrous oxides and sulfur dioxide emissions when the cap-and-trade system began in 1990: scrubbers on the smokestacks. Even though the U.S. Congress could have ordered industry to buy the scrubbers, it was easier to pass cap-and-trade politically, and only a certain sector of energy production emits a significant volume of these chemicals. Today, there isn’t consensus about the effects of carbon dioxide gas, which isn’t toxic to humans. There isn’t consensus about how much carbon emissions is acceptable, and there is no viable carbon capture technology. And more than 80 percent (by volume) of energy production methods still produce carbon dioxide, whether that’s from biofuels or coal.

CAP-AND-TRADE IN EUROPE

In 2005, the European Union passed its own cap-and-trade program to limit carbon dioxide emissions, applied to more than 12,000 factories and power plants in 29 countries. The program includes some limits to nitrous oxide, and airlines will be obliged to participate by 2012. The carbon “cap” on total emissions decreases 1.74% per year.

Some regulators have already claimed success, as the carbon dioxide emissions were reduced in 2009; they increased again a little in 2010. However, the EU admits it gave out too many permits and that future permits will need to be tighter. Furthermore, the recession has acted as a major factor in lowered emissions, and European industries haven’t needed to make any technological changes because of lower demand.

“Power companies were given free carbon permits, but they raised electricity fees anyway — as if they had paid the market price for their permits — and pocketed the markup. Many companies were allocated too many allowances, often the result of powerful industries lobbying the governments that give the permits,” Arthur Max of The Associated Press wrote from Belgium in a 2011 story about the Europeans’ progress.

If the EU’s carbon dioxide emissions will be reduced in coming years has yet to be determined since the real effects of the cap haven’t truly set in.

CAP-AND-TRADE IN INDIVIDUAL STATES

Ten states in the Northeast have applied a cap-and-trade system to carbon dioxide as of 2008, in the Regional Greenhouse Gas Initiative, with the goal of reducing greenhouse gas 10 percent by 2018.

California is planning its own cap-and-trade program, slated to begin December 2011. Ten Canadian provinces and Western U.S. states and have joined California in the Western Climate Initiative, with the hope that there will be a regional cap-and-trade program too.

CARBON TAX

Carbon taxes are another way to integrate emissions reductions into the economy. The taxes makes a beeline for fossil fuels, which are far and away the main source of carbon dioxide emissions, whether they’re burned in vehicles or for electricity. A carbon tax on fuels raises the overall price, in theory reducing our ability to buy too much. That means that industries or individuals can still produce as much carbon dioxide as they please, but they’ll have to pay for it.

Some economists prefer carbon taxes, as they are simpler to enforce, particularly internationally, and there’s likely to be less dramatic shifts in pricing. Others prefer cap-and-trade because there’s a finite ceiling to emissions. Many other arguments support either measure.

From a carbon tax perspective, diesel fuel and natural gas have an advantage over gasoline and coal, respectively, since they produce less carbon dioxide for the energy they generate. Of course, solar and wind produce none, but biofuels are more complex. Many carbon taxes in effect exclude biofuels like wood waste, even though they produce carbon dioxide.

Several European countries and individual U.S. states have various carbon taxes, applied from anywhere in the range of cents to close to $100 per ton, about as much carbon dioxide as would be emitted from using roughly 103 gallons of gasoline. These taxes are still low enough that they aren’t halting emissions. (For more details about calculating carbon emissions, seeThe Intergovernmental Panel on Climate Change.)

In the United States, carbon taxes in individual states are currently insignificant compared to other market pressures on the price of fuels, particularly in the case of petroleum.